Change hacking.py N306 to use logical_lines
Change hacking.py N306 to use logical_lines

Only logical lines (does not include comments) should be checked for
alphabetical import order.  This patch changes N306
(imports not in alphabetical order) to run on logical lines not physical lines.

Fixes bug 1071849

Change-Id: Ib2cb92f9eb82aeed1ff5879d3e38c8961b4f06cc

openstack-dev/hacking,emonty/oslo-hacking,hyakuhei/cleantox,zancas/hacking,hyakuhei/cleantox,openstack-dev/hacking,emonty/oslo-hacking,zancas/hacking